Need help with a question about interchangeable parts

[Beau Abbott]

Quick question can you put a series one plenum onto a series 2, if so what is needed to be one to make it work. Have only ever found info the other way around.

 

[VPRob]

I'm not 100% sure but I would think the plenum cover from VN series 1 to VP series 2 would all be interchangeable. I don't know about VR to VS.

 

[Immortality]

Do you mean a series one intake manifold on a series 2 engine?

Yes and no. One of the big changes between the series 1 and 2 engines is the PCV system part of which isn't really interchangeable. One uses breather holes through the side of the manifold into the head where as the other doesn't.

The series one also has the breather hose from the bottom of the TB to the rocker cover, the series doesn't have that either IIRC.

 

[Sandst4rm]

My car has a series 1 block that came with series 2 intake on it, the crankcase develops a substantial amount of pressure, enough to blast oil out of the sump gasket and dipstick, or blow the oil cap out of your hand when running and trying to take it off, I've sourced a series 1 alloy rocker cover with breather and i will let you know if that fixes it when i get mine back together.
I'm going to combine the S2 PCV hose with the S1 rocker breather with a T piece and route it to the normal intake hole for S2

It is worth noting that with the oil cap removed there isn't piston blowby and no oil comes out of the dipstick or sump (pressure relieved)

 

[Immortality]

This should explain it all,

https://forums.justcommodores.com.au/threads/vn-v6-intake-manifold-head-difference-between-series-one-and-series-2-vp-vr.37943/

 

[MikeC]

My car has a series 1 block that came with series 2 intake on it, the crankcase develops a substantial amount of pressure, enough to blast oil out of the sump gasket and dipstick, or blow the oil cap out of your hand when running and trying to take it off, I've sourced a series 1 alloy rocker cover with breather and i will let you know if that fixes it when i get mine back together.
I'm going to combine the S2 PCV hose with the S1 rocker breather with a T piece and route it to the normal intake hole for S2

It is worth noting that with the oil cap removed there isn't piston blowby and no oil comes out of the dipstick or sump (pressure relieved)

Do you have annual roadworthies in SA? I've got a 1998 MB SLK where I've vented the crankcase with a hose down to the atmosphere alongside the gearbox for the last 10 years- SLK's have a real problem with oil contamination of the MAF with their original setup venting back into the intake tract.

The same setup would work with your car- you're getting the same amount of piston blowby whether the oil cap is on or off but it vents it out easier with the cap off.

 

[Sandst4rm]

Do you have annual roadworthies in SA? I've got a 1998 MB SLK where I've vented the crankcase with a hose down to the atmosphere alongside the gearbox for the last 10 years- SLK's have a real problem with oil contamination of the MAF with their original setup venting back into the intake tract.

The same setup would work with your car- you're getting the same amount of piston blowby whether the oil cap is on or off but it vents it out easier with the cap off.

No annual roadworthy over here.

Yes I know engines have some blowby, but with no PCV system at all on account that the heads have no holes drilled to vent to the intake. The crankcase is essentially sealed so that's why mine builds pressure.

 

[MikeC]

No annual roadworthy over here.

Yes I know engines have some blowby, but with no PCV system at all on account that the heads have no holes drilled to vent to the intake. The crankcase is essentially sealed so that's why mine builds pressure.

I agree, if your crankcase is completely sealed it will build up pressure so it must be vented- the simple vent I use on the MB is bullet proof. But I'm not going to push it as it's also completely illegal for road use.

 

[Fu Manchu]

You have to vent them. Without venting, the pressure will result in oil leaks from every possible weak point.

It won’t leak straight away, but it will happen within the year.

Keep the PCV working, it’s the right thing to do for your motor.

 

[Sandst4rm]

I got those alloy covers from a S1 VN with a factory breather and it doesn't build pressure anymore.

My PCV system in my S2 intake is non functional because the heads have no holes in the PCV side (s1 heads) and I was unable to link the two together so I just vented the rocker cover to the atmosphere behind the throttle